As disclosed in patent literature 1, a component mounter picks up an electronic component at a supply position using a suction nozzle and mounts the electronic component at specified coordinates (mounting position) on a circuit board. For a circuit board on which multiple electronic components have been mounted by a component mounter, the mounting state of the electronic components is automatically inspected by a visual inspection device positioned downstream to the component mounter in a production line (refer to patent literature 2). The mounting state of electronic components includes things such as the deviation amount of an electronic component with respect to the mounting position, the orientation of an electronic component, and the presence of damage.
Also, inspection of circuit boards, in addition to automatic inspection by a visual inspection device of a target circuit board for which mounting is complete, includes manual visual inspection by an operator of a target circuit board for which mounting is still being performed. Visual inspection, for example, is required when mounting electronic components that require particularly mounting accuracy, or components that are easily damaged. During visual inspection, an operator visually checks electronic components that are targets for inspection mounted on the circuit board and determines whether the mounting state is good or bad.